On 03/23/2015 05:00 PM, Petr Kulhavy wrote:
> If edma_terminate_all() was called while a transfer was running (i.e. after
> edma_execute() but before edma_callback()) the echan->edesc was not freed.
>
> This was due to the fact that a running transfer is on none of the
> vchan lists: desc_submitted, desc_issued, desc_completed (edma_execute()
> removes it from the desc_issued list), so the vchan_dma_desc_free_list()
> called at the end of edma_terminate_all() didn't find it and didn't free it.
It is another question if it is really correct to remove the the currently
running desc from the issued list in edma_execute().
Based on what I have seen some drivers using virt-dma does this while others not.
Russel, do you have any advice on this?
Will this work for you to fix the leak:
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 7b65633f495e..ea8544481245 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -162,7 +162,6 @@ static void edma_execute(struct edma_chan *echan)
echan->edesc = NULL;
return;
}
- list_del(&vdesc->node);
echan->edesc = to_edma_desc(&vdesc->tx);
}
@@ -760,6 +759,7 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
dev_dbg(dev, "Transfer complete, stopping channel %d\n", ch_num);
edesc->residue = 0;
edma_stop(echan->ch_num);
+ list_del(&edesc->vdesc.node);
vchan_cookie_complete(&edesc->vdesc);
edma_execute(echan);
} else {
> This bug was found on an AM1808 based hardware (very similar to da850evm,
> however using the second MMC/SD controller), where intense operations on the SD
> card wasted the device 128MB RAM within a couple of days.
>
> Signed-off-by: Petr Kulhavy <petr@xxxxxxxxx>
> ---
> drivers/dma/edma.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
> index 276157f..1465610 100644
> --- a/drivers/dma/edma.c
> +++ b/drivers/dma/edma.c
> @@ -260,6 +260,14 @@ static int edma_terminate_all(struct dma_chan *chan)
> */
> if (echan->edesc) {
> int cyclic = echan->edesc->cyclic;
> +
> + /*
> + * free the running request descriptor
> + * since it is on none of the vchan lists
> + * desc_submitted, desc_issued, desc_completed
> + */
> + kfree(echan->edesc);
If we do this I would prefer to have:
edma_desc_free(&echan->edesc->vdesc);
> +
> echan->edesc = NULL;
> edma_stop(echan->ch_num);
> /* Move the cyclic channel back to default queue */
>
--
Péter
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